You already got your answer from your other post.
https://forums.tomshardware.com/thr...but-i-can-only-see-one.3568169/#post-21541700
"
Edit - I looked up the specs of the CPU and it only has a single memory channel, so adding a module with higher than 4GB capacity won't matter since you can't run dual channel mode. Get an 8 or 16GB 2133Mhz module if you really need more than 8GB. "
And here is the exact information you are looking for.
http://www.cpu-world.com/CPUs/Bulldozer/AMD-A9-Series A9-9420e.html
Memory controller | The number of controllers: 1
Memory channels: 1 <---------- Single Channel
Supported memory: DDR4-2133
Maximum memory bandwidth (GB/s): 17.1 |
That's your CPU. It does not have Dual Channel support.